<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class UUID {
	public function v3($namespace, $name) {
		if(!self::is_valid($namespace)) return false;

		// Get hexadecimal components of namespace
		$nhex = str_replace(array('-','{','}'), '', $namespace);

		// Binary Value
		$nstr = '';

		// Convert Namespace UUID to bits
		for($i = 0; $i < strlen($nhex); $i+=2) {
			$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
		}

		// Calculate hash value
		$hash = md5($nstr . $name);

		return sprintf('%08s-%04s-%04x-%04x-%12s',

		// 32 bits for "time_low"
		substr($hash, 0, 8),

		// 16 bits for "time_mid"
		substr($hash, 8, 4),

		// 16 bits for "time_hi_and_version",
		// four most significant bits holds version number 3
		(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x3000,

		// 16 bits, 8 bits for "clk_seq_hi_res",
		// 8 bits for "clk_seq_low",
		// two most significant bits holds zero and one for variant DCE1.1
		(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,

		// 48 bits for "node"
		substr($hash, 20, 12)
		);
	}

	public function v4() {
		return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',

		// 32 bits for "time_low"
		mt_rand(0, 0xffff), mt_rand(0, 0xffff),

		// 16 bits for "time_mid"
		mt_rand(0, 0xffff),

		// 16 bits for "time_hi_and_version",
		// four most significant bits holds version number 4
		mt_rand(0, 0x0fff) | 0x4000,

		// 16 bits, 8 bits for "clk_seq_hi_res",
		// 8 bits for "clk_seq_low",
		// two most significant bits holds zero and one for variant DCE1.1
		mt_rand(0, 0x3fff) | 0x8000,

		// 48 bits for "node"
		mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
		);
	}

	public function v5($namespace, $name) {
		if(!self::is_valid($namespace)) return false;

		// Get hexadecimal components of namespace
		$nhex = str_replace(array('-','{','}'), '', $namespace);

		// Binary Value
		$nstr = '';

		// Convert Namespace UUID to bits
		for($i = 0; $i < strlen($nhex); $i+=2) {
			$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
		}

		// Calculate hash value
		$hash = sha1($nstr . $name);

		return sprintf('%08s-%04s-%04x-%04x-%12s',

		// 32 bits for "time_low"
		substr($hash, 0, 8),

		// 16 bits for "time_mid"
		substr($hash, 8, 4),

		// 16 bits for "time_hi_and_version",
		// four most significant bits holds version number 5
		(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x5000,

		// 16 bits, 8 bits for "clk_seq_hi_res",
		// 8 bits for "clk_seq_low",
		// two most significant bits holds zero and one for variant DCE1.1
		(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,

		// 48 bits for "node"
		substr($hash, 20, 12)
		);
	}

	public function is_valid($uuid) {
		return preg_match('/^\{?[0-9a-f]{8}\-?[0-9a-f]{4}\-?[0-9a-f]{4}\-?'.
                      '[0-9a-f]{4}\-?[0-9a-f]{12}\}?$/i', $uuid) === 1;
	}
}
